Anticancer activity of cis-diamine platinum(ii) complexes of thiones

ABSTRACT

A method for treating a proliferative disease, disorder, or condition comprising administering a cis-diamine platinum(II) thione complex. A cis-diamine platinum(II) thione complex and compositions containing it.

BACKGROUND Field of the Invention

The present disclosure relates to cis-amine Pt(II) thione complexeshaving the general formula, cis-[Pt(NH₃)₂(Thione)₂].2NO₃ and to a methodfor treating or inhibiting cancer using them.

Description of Related Art

The “background” description provided herein is for the purpose ofgenerally presenting the context of the disclosure. Work of thepresently named inventor(s), to the extent it is described in thisbackground section, as well as aspects of the description which may nototherwise qualify as prior art at the time of filing, are neitherexpressly or impliedly admitted as prior art against the presentinvention.

Cisplatin is known to be one of the most effective drugs for thetreatment of a variety of cancers. See T. C. Johnstone, K.Suntharalingam, S. J. Lippard, Chem. Rev. 116 (2016) 3436-3486; S.Dilruba, G. V. Kalayda, Cancer Chemotherapy and Pharmacology. 77 (2016)1103-1124; N. J Wheate, S. Walker, G. E Craig, and R. Oun. Dalton Trans.39 (2010) 8113-8127; J. J. Wilson, S. J. Lippard, Chem. Rev. 114 (2014)4470-4495; Y. Jung, S. J. Lippard, Chem, Rev. 107 (2007) 1387-1407; D.Wong, S. J. Lippard, Nat. Rev, Drug Disc. 4 (2005) 307-320; K. SLovejoy, S. J Lippard. Dalton Trans. (2009) 10651-10659; L. Kelland. NatRev Cancer. 7 (2007) 573-584; J. Reedijk, Eur, J. Inorg. Chem. (2009)1303-1312; and S. Dasari, P. B. Tchounwou, Eur. J. Pharmacol. (2014)364-378, each incorporated herein by reference in their entirety.However, the therapeutic use of cisplatin also leads to several sideeffects (e.g., nephrotoxicity and neurotoxicity) and drug resistance.See Dasair et al.; A. Florea and D. Büsselberg, Cancers (toxicity). 3(2011) 1351-1371; J. T Hartmann and H. P. Lipp. Expert Opin.Pharmacother. 4 (2003) 889-901; V. M. Piccolini, M. G. Bottone, G.Bottiroli, S. A. De Pascali, F. P. Fanizzi, G. Bernocchi, Cell BiolToxicol. 29 (2013) 339-353; L. Galluzzi, L. Senovilla, I. Vitale, J.Michels, 1. Martins, O. Kepp, M. Castedo, G. Kroemer, Oncogene. 31(2012) 1869-1883; D. J. Stewart, Crit. Rev. Oncol. Hematol. 63 (2007)12-31; and J. Zisowsky, S. Koegel, S. Leyers, K. Devarakonda, M. U.Kassack, M. Osmak, U. Jaehde, Biochem. Pharmacol. 73 (2007) 298, eachincorporated herein by reference in their entirety. Due to theselimitations, efforts are continued to develop more effective drugs inorder to reduce the toxicity of cisplatin and to overcome the cellularor inherent resistance. As a result, thousands of platinum compoundshave been prepared and evaluated to check their anticancer effect. But,only a few of them have entered human clinical trials. See T. C.Johnstone et al.; S. Dilruba et al; N. J. Wheate et al.; J. J. Wilson etal; M. C. Ackley, C. G. Barry, A. M. Mounce, M. C. Farmer, B. E.Springer, C. S. Day, M. W. Wright, S. J. Berners-Price, S. M. Hess, U.Bierbach, J. Biol. Inorg. Chem. 9 (2004) 453; M. Galanski, M. A.Jakupec, B. K. Keppler, Curr. Med. Chem. 12 (2005) 2075-2094; E.Escribano, M. Font-Bardia, I. Calvet, J. Lorenzo, P. Gamez, V. Moreno,Inorg. Chim. Acta 394 (2013) 65-76; D Lebwohl, R. Canett. Eur. J. Cancer34 (1998) 1522-1534 ; C. Gao, S. Gou, G. Xu, Chem. Pharm. Bull. 59(2011) 851-854; B. A. Miles, A. E. Patterson, C. M. Vogels, A. Decken,J. C. Waller, P.-Jr. Morin, S. A. Westcott, Polyhedron 108 (2016) 23-29;G. Tamasi, M. Casolaro, A. Magna i A. Sega, L. Chiasserini, L. Messori,C. Gabbiani, S.M Valiandi, A. Michael, Jakupec, B. K. Keppler, B.Michael Hursthouse, R. Cini, J. Inorg. Biochem. 104 (2010) 799-814; R.Yin, S. Gou, X. Liu, L. Lou, J. Inorg. Biochem. 105 (2011) 1095-1101; W.Tian , L. He, Research on Chemical Intermediates. 41 (2015) 8725-8733;U. Kalinowska-Lis, J. Ochocki, K. Matlawska-Wasowska, Coord, Chem. Rev252 (2008) 1328-1345; I. Kostova, Recent Patents on Anti-Cancer DrugDiscovery.1 (2006) 1-22; and M. Fanelli, M. Formica, V. Fusi, L. Giorgi,M. Micheloni, and P. Paoli, Coord. Chem Rev. 310 (2016) 41-79, eachincorporated herein by reference in their entirety. Most of theclinically effective compounds have common structural unit (cis-PtN₂) ascisplatin. The biological activity associated with these compounds isnormally associated with the presence of two fairly labile cis ligands,e.g, the two chlorido groups in cisplatin. See M. Fanelli et al.; E. RJamieson, S. J Lippard. Chem Rev., 99 (1999) 2467-2498; and S. Ahmad, A.Isab, S, Ali, Transition Met. Chem. 31 (2006) 1003-1016, eachincorporated herein by reference in their entirety. The Pt-DNA adductsproduced by cisplatin and many of its analogues are almost identical,and would explain their similar patterns of tumor sensitivity andsusceptibility to resistance. These adducts after cellular processinginhibit the normal transcription or replication of DNA and eventuallylead to cell death. See T. C. Johnstone et al.; S. Dilruba et al; N. J.Wheate et al; J. J. Wilson et al.; Y. Jung et al.; D. Wong et al.; K. S.Lovejoy et al.; L. Kelland; J. Reedijk; S. Dasari et al.; E. R. Jamisonet al.; S. Ahmad, A. Isab, S. Ali, Transition Met. Chem. 31 (2006)1003-1016; S. Ahmad, Chem & Biodiver. 7 (2010) 543-566; S. G. Chaney, S.L. Campbell, E. Bassett, Y. Wu, Crit. Rev. Oncol. Hematol. 53 (2005)3-11; S. V. Zutphen, J. Reedijk, Coord. Chem. Rev. 249 (2005) 2845-2853;S. Komeda. Metallomics, 3 (2011) 650-655; and J. Reedijk, Chem. Rev. 99(1999) 2499, each incorporated herein by reference in their entirety.

Some platinum(II) complexes with sulfur-containing ligands such asdithiocarbamates, thiosemicarbazones and thioureas have shown superioror equal efficacy towards some human tumor cell lines and with lesstoxicity than cisplatin. See D. Fregona, L. Giovagnini, L. Ronconi, C.Marzano, A. Trevisan, S. Sitran, B. Biondi, F. Bordin, J. Inorg.Biochem. 93 (2003) 181-189; G. Faraglia, D. Fregona, S. Sitran, L.Giovagnini, C.Marzano, F. Baccichetti, U. Casellato, R. Graziania, J.Inorg. Biochem. 83 (2001) 31-40; L. Giovagnini, L. Ronconi, D.Aldinucci, D. Lorenzon, S. Sitran, D. Fregona. J. Med, Chem. 48 (2005)1588; D. Kovala-Demertzi, P. N. Yadav, M. A. Demertzis, M. Coluccia. J.Inorg. Biochem. 78 (2000) 347; A. G. Quiroga, and C. N. Ranninger,Coord. Chem. Rev. 248 (2004) 119-133; D. Kovala-Demertzi, A.Papageorgiou, L. Papathanasis, A. Alexandratos, P. Dalezis, J. R.Miller, M. A. Demertzis, Eur. J. Med. Chem. 44 (2009) 1296-1302 ; G.Marverti, M. Cusumano, A. Ligabue, M. L. Di Pietro, P. A. Vainiglia, A.Ferrari, M. Bergomi, M. S. Moruzzi, C. Frassineti, J. Inorg. Biochem.102 (2008) 699-712 ; L. Fuks, E. Anuszewska, H. Kruszewska, A.Krowczynski, J. Dudek, N. Sadlej-Sosnowska, Transition Met. Chem, 35(2010) 639-647; A. Z. A. Mustafa, M. Altaf, M. Monim-ul-Mehboob, M.Fettouhi, M. I. M Wazeer, A. A Isab, V. Dhuna, G. 13hatia, K. Dhuna,Inorg. Chem. Commun. 44 (2014) 159-163; and A. Zainelabdeen A. Mustafa,M. Monim-ul-Mehboob, M. Y. Jomaa, M. Altaf, M, Fettouhi, A. A. Isab, M.I. M. Wazeer, H, Stoeckli-Evans, G. Bhatia, V. Dhuna, J. Coord. Chem. 68(2015) 3511-3524, each incorporated herein by reference in theirentirety. Sulfur-containing molecules are also under study aschemoprotectants in platinum-based drugs chemotherapy. See S. Ahmad, A.Isab, S. Ali, Transition Met. Chem. 31 (2006) 1003-1016; and M.Galanski, each incorporated herein by reference in their entirety. Thesestudies show that there is a significant potential in the studies ofPt(II) complexes of sulfur donor ligands such as thiones. Several thionederivatives of cisplatin displaying antitumor activities have also beenreported. See G. Marverti, incorporated herein by reference in itsentirety. To explore further about the antitumor potential ofplatinum-thione complexes, herein is disclosed the synthesis,spectroscopic characterization and anticancer activities of a number ofcis-platinum(II) complexes with heterocyclic thiones ligand such asimidazolidine-2-thione (Imt), diazinane-2-thione (Diaz) and theirderivatives as given in scheme 1.

The synthesis of these complexes and characterization by elementalanalysis, IR and NMR (¹H & ¹³C) methods is one object of the presentdisclosure. It is a further object of the disclosure to comparespectroscopic data with the coordination of thiones to platinum(II) andshow in vitro cytotoxic properties of all these complexes against threehuman cancer cell lines, which include; A549 (human lung carcinoma),MCF-7 (human breast carcinoma) and HTCIS (human colon cancer), incompareison to the therapeutically used anticancer agents cisplatin andcarboplatin. The in vitro cytotoxicities in several cases are,comparable to cisplatin and higher than carboplatin.

BRIEF SUMMARY OF THE INVENTION

The following provides a summary of certain exemplary embodiments of thepresent invention. This summary is not an extensive overview and is notintended to identify key or critical aspects or elements of the presentinvention or to delineate its scope.

The invention is directed to platinum(II) complexes with thiones and tomethods of treating cancer using these complexes. Several classes andten complexes are exemplified; that is Complexes 1, 2, 3, 4, 5, 6, 7, 8,9 and 10. The invention includes these complexes as well as theirstructural variants, for example, complexes containing substitutedamines, substituted thiones, or those containing anions other than NO₃.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing summary, as well as the following detailed description ofpreferred embodiments of the invention, will be better understood whenread in conjunction with the appended drawings. It should be understood,however, that the invention is not limited to the precise features,arrangements, or instrumentalities shown.

FIG. 1. General formula for cis-diamine Pt(II) thione complexes of theinvention. In some embodiments, the HN groups may be further substitutedwith non-hydrogen substituents.

FIGS. 2A, 2B and 2C. Some examples of cis-diamine Pt(II) thionecomplexes. It can be clearly seen that form the structures the Pt(II)centre bounded to two amine ligands and two thione ligands via sulfurdonor atoms in cis geometry. A trans geometry is the opposite with thesame formula.

FIG. 3A. Comparison of antitumor activity and DNA binding of cis-diaminecomplexes and trans-diamine complexes. The Pt(II) complexes of theinvention are cis-isomers which contribute to their biologicalanticancer activity. Complexes having a trans geometry, such astrans-platins, have been found to be less active. Cis- and transcompounds bind to DNA in different ways and produce different biologicaleffects.

FIG. 3B depicts intra-strand crosslink via cis-diamine Pt(II) complex.Platination can form different DNA adducts. It was found that 60-65% ofthe formed adducts are 1, 2-d(GpG) intrastrand cross-links binding withtwo neighbouring guanine in the same strand, which can be achieved onlythrough cis configuration

FIG. 3C depicts interaction of a Pt(II) complex with guanine.

FIGS. 4A and 4B. Activity of complexes (1)-(10) on A549 cells comparedto Cisplatin. A549 is a human lung carcinoma cell line.

FIGS. 5A and 5B. Activity of complexes (1)-(10) on MCF7 cells comparedto Cisplatin. MCF7 is a human breast carcinoma cell line.

FIGS. 6A and 6B. Activity of complexes (1)-(10) on HCTI5 cells comparedto Cisplatin.

DETAILED DESCRIPTION OF THE INVENTION

The invention is directed to cis-diamine platinum(11) thione complexeswith thione ligands as shown by FIG. 1 or FIG. 2, including complexes(1), (2), (3), (4), (5), (6), (7), (8), (9) and (10), the corestructures of these complexes, chemical variants of these corestructures, and to methods that induce cytotoxicity in cancer or tumorcells.

The present disclosure will be better understood with reference to thefollowing definitions:

As used herein “compound” and “complex” are used interchangeably and areintended to refer to a chemical entity, whether in a solid, liquid orgaseous phase and whether in a crude mixture or a purified and isolatedform. For example, cis-diamino platinum(II) thione complex (1) of theinvention may be referred to as 1, complex 1, or compound 1 andsimilarly with regard to other enumerated complexes disclosed herein.

Platinum(II) or Pt(II) describes platinum in an oxidation state of +2.One example of a platinum(II) compound is platinum chloride having thechemical formula PtCl₂.

Thiones include but are not limited to those described by the formulasbelow, wherein R is a suitable substituent that does not substantiallyeliminate the therapeutic properties of a cis-diamine Pt(II) thionecomplex produced with the substituted thione:

In some embodiments, the thiones may be further substituted on thecarbons at ring positions 4, 5, 6, or 7 described in the rings above.Such substituents include those disclosed herein as other substituents.

Specific thiones exemplified herein include the following:

wherein thiones (a)-(j) are substituted as follows: (a) R═R′═H;Imidazolidine-2-thione (Imt), (b) R═H, R′═CH₃;N-methylimid.azolidine-2-thione (MeImt), (c) R═CH₃, R′═CH₃;N,N′-dimethylimidazolidine-2-thione (Me₂Imt), (d) R═R′═C₂H₅;N,N′-diethylimidazolidine-2-thione (Et₂Imt), (e) R═H, R′═C₃H₇;N-propylimidazol dine-2-thione (PrImt), (f) R═H, R′=i-C₃H₇;N-(isopropyl)imidazolidine-2-thione (iPrImt), (g) R═R′=i-C₃H₇;N,N′-(diisopropyl)imidazolidine-2-thione (iPr₂Imt), (h) R═H;1,3-Diazinane-2-thione (Diaz), (i) R═C₂H₅;N-ethyl-1,3-Diazinane-2-thione (EtDiaz), (j) 1,3-Diazepane-2-thione(Diap).

The terms “union” or “counter-anion” refer to an anion, preferably apharmaceutically acceptable anion that is associated with a positivelycharged platinum(II) complex core. Non-limiting examples ofpharmaceutically acceptable counter-anions include nitrate, halides suchas fluoride, chloride, bromide, iodide; sulfate; phosphate; amide;methanesulfonate; ethanesulfonate; p-toluenesulfonate, salicylate,malate, maleate, succinate, tartrate; citrate; acetate; perchlorate;trifluoromethanesulfonate (triflate); acetylacetonate;hexafluorophosphate; and hexafluoroacetylacetonate.

Amines. The amine components of the complex, independently, have theformula NR1R2, where R1 and R2 may both be hydrogen, one of R1 or R2 maybe hydrogen, or neither R1 or R2 is hydrogen. Non-hydrogen substituentsinclude alkyl, such as C1-C6 alkyl or aryl either of which may befurther substituted. Other substituents disclosed herein may also beused provided they do not negate the cytotoxic activity of a platinu(II)complex.

Variants. Structurally-related variants of the complexes exemplifiedherein include cis-diamine Pt(II) complexes where at least one of R1 andR2 on the amine group has a non-hydrogen substituent, such as alkyl(e.g., C₁-C₆ alkyl) or aryl; complexes where the thione component issubstituted, and/or complexes wherein the one or both NO₃ anions arereplaced with another anion. Heterocyclic thiones are stable ligands andcan be substituted often without substantial effects on a cis-diaminePt(II) thione complex's therapeutic, cytotoxic or anti-cancerproperties.

Other substituents that may appear on the amine (i.e., as R₁ and/or R₂)and thione components of the Pg(II) complex include but are not limitedthose defined below.

Alkyl, as used herein, which unless otherwise specified, refers to astraight or branched hydrocarbon fragment such as a C₁-C₆ group.Non-limiting examples of such hydrocarbon fragments include methyl,ethyl, propyl, isopropyl, butyl, isobutyl, t-butyl, pentyl, isopentyl,neopentyl, hexyl, isohexyl, 3-methylpentyl, 2,2-dimethylbutyl, and2,3-dimethylbutyl. As used herein, the term “cycloalkyl” refers to acyclized alkyl group. Exemplary cycloalkyl groups include, but are notlimited to, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, norbornyl,and adamantyl. Branched cycloalkyl groups, for example,1-methylcyclopropyl and 2-methycyclopropyl groups, are included in thedefinition of cycloalkyl as used in the present disclosure. The term“alkenyl” refers to a straight, branched, or cyclic hydrocarbon fragmentcontaining at least one C=C double bond. Exemplary alkenyl groupsinclude, without limitation, 1-propenyl, 2-propenyl (or “allyl”),1-butenyl, 2-butenyl, 3-butenyl, 1-pentenyl, 2-pentenyl, pentenyl,4-pentenyl, 1-hexenyl, 2-hexenyl, 3-hexenyl, 4-hexenyl, 5-hexenyl,1-heptenyl, 2-heptenyl, 3-heptenyl, 4-heptenyl, 5-heptenyl, 6-heptenyl,1-octenyl, 2-octenyl, 3-octenyl, 4-octenyl, 5-octenyl, 6-octenyl,7-octenyl, 1-nonenyl, 2-nonenyl, 3-nonenyl, 4-nonenyl, 5-nonenyl,6-nonenyl, 7-nonenyl, 8-nonenyl, 1-decenyl, 2-decenyl, 3-decenyl,4-decenyl, 5-decenyl, 6-decenyl, 7-decenyl, 8-decenyl, and 9-decenyl,The term “aryl”, as used herein, and unless otherwise specified, refersto phenyl, biphenyl, naphthyl, anthracenyl, and the like. The term“heteroaryl” refers to an aryl group where at least one carbon atom isreplaced with a heteroatom (e.g. nitrogen, oxygen, sulfur) and can beindolyl, furyl, imidazolyl, triazolyl, triazinyl, oxazolyl, isoxazolyl,thiazolyl, isothiazolyl, pyrazolyl, pyrrolyl, pyrazinyl, tetrazolyl,pyridyl (or its N-oxide), thienyl, pyrimidinyl (or its N-oxide),IH-indolyl, isoquinolyl (or its N-oxide), or quinolyl (or its N-oxide),for example. As used herein, the term “substituted” refers to at leastone hydrogen atom that is replaced with a non-hydrogen group, providedthat normal valencies are maintained and that the substitution resultsin a stable compound. When a compound or a R group is noted as“optionally substituted”, the substituents are selected from theexemplary group including, but not limited to, aroyl (as definedhereinafter); halogen (e.g. chlorine, bromine, fluorine or iodine);alkoxy (i.e. straight or branched chain alkoxy having 1 to 10 carbonatoms, and includes, for example, methoxy, ethoxy, propoxy, isopropoxy,butoxy, isobutoxy, sec-butoxy, tert-butoxy, pentoxy, isopentoxy,hexyloxy, heptyloxy, octyloxy, nonyloxy, and decyloxy); cycloalkyloxyincluding cyclopentyloxy, cyclohexyloxy, and cycloheptyloxy; aryloxyincluding phenoxy and phenoxy substituted with halogen, alkyl, alkoxy,and haloalkyl (which refers to straight or branched chain alkyl having 1to 8 carbon atoms which are substituted by at least one halogen, andincludes, for example, chloromethyl, bromomethyl, fluoromethyl,iodomethyl, 2-chloroethyl, 2-bromoethyl, 2-fluoroethyl, 3-chloropropyl,3-bromopropyl, 3-fluoropropyl, 4-chlorobutyl, 4-fluorobutyl,dichloromethyl, dibromomethyl, difluoromethyl, diiodomethyl,2,2-dichloroethyl, 2,2-dibromoethyl, 2,2-difluoroethyl,3,3-dichloropropyl, 3,3-difluoropropyl, 4,4-dichlorobutyl,4,4-difluorobutyl, trichloromethyl, trifluoromethyl,2,2,2-tri-fluoroethyl, 2,3,3-trifluoropropyl, 1,1,2,2-tetrafluoroethyl,2,2,3,3-tetratluoropropyl); hydrocarbyl; arylalkyl; hydroxy; alkoxy;oxo; alkanoyl; alkanoyloxy; amino; alkylamino; arylamino;arylalkylamino; disubstituted amines (e.g., in which the two aminosubstituents are selected from a group including, but not limited to,alkyl, aryl, or arylalkyl); alkanoylamino; thiol; alkylthio; arylthio;arylalkylthio; alkylthiono; arylthiono; aryalkylthiono; alkylsulfonyl;arylsulfonyl; arylalkylsulfonyl; sulfonamido (e.g. —SO₂NH₂); substitutedsulfonamide; nitro; cyano; carboxy; carbamyl (e.g., —CONH₂, —CONHalkyl,—CONHaryl, —CONHarylalkyl or cases where there are two substituents onone nitrogen from alkyl, aryl, or arylalkyl); alkoxycarbonyl; aryl;heteroarylcarbonyl; heterocyclyl; and mixtures thereof and the like. Thesubstituents may be either unprotected, or protected as necessary, asknown to those skilled in the art, for example, as taught in Greene, etal., “Protective Groups in Organic Synthesis”, John Wiley and Sons,Second Edition, 1991, hereby incorporated by reference in its entirety).The term “heterocyclyl” as used in this disclosure refers to a 3-8,preferably 4-8, more preferably 4-7 membered monocyclic ring or a fused8-12 membered bicyclic ring which may be saturated or partiallyunsaturated, which monocyclic or bicyclic ring contains 1 to 4heteroatoms selected from oxygen, nitrogen, silicon, or sulfur. Examplesof such monocyclic rings include oxaziridinyl, homopiperazinyl,oxiranyl, dioxiranyl, aziridinyl, pyrrolidinyl, azetidinyl,pyrazolidinyl, oxazolidinyl, piperidinyl, piperazinyl, morpholinyl,thiomorpholinyl, thiazolidinyl, hydantoinyl, valerolactamyl, oxiranyl,oxetanyl, dioxolanyl, dioxanyl, oxathiolanyl, oxathianyl, dithianyl,dihydrofuranyl, tetrahydrofuranyl, dihydropyranyl, tetrahydropyranyl,tetrahydropyridyl, tetrahydropyrimidinyl, tetrahydrothiophenyl,tetrahydrothiopyranyl, diazepanyl, and azepanyl. Examples of suchbicyclic rings include indolinyl, isoindolinyl, benzopyranyl,quinuclidinyl, 2,3,4,5-tetrahydro-1,3,benzazepine,4-(benzo-1,3,dioxol-5-methyl)piperazine, and tetrahydroisoquinolinyl.Further, “substituted heterocyclyl” may refer to a heterocyclyl ringwhich has additional (e.g. one or more) oxygen atoms bonded to the ringatoms of parent heterocylcyl ring. An example of a heterocyclylsubstituted with one or more oxygen atoms is1,1-dioxido-1,3-thiazolidinyl. The term “alkylthio” as used in thisdisclosure refers to a divalent sulfur with alkyl occupying one of thevalencies and includes the groups methylthio, ethylthio, propylthio,butylthio, pentylthio, hexylthio, and octylthio. The term “alkanoyl” asused in this disclosure refers to an alkyl group having 2 to 18 carbonatoms that is bound with a double bond to an oxygen atom. Examples ofalkanoyl include, acetyl, propionyl, butyryl, isobutyryl, pivaloyl,valeryl, hexanoyl, octanoyl, lauroyl, and stearoyl. Examples of aroylare benzoyl and naphthoyl, and “substituted aroyl” may refer to benzoylor naphthoyl substituted by at least one substituent including thoseselected from halogen, amino, nitro, hydroxy, alkyl, alkoxy andhaloalkyl on the benzene or naphthalene ring. The term “arylalkyl” asused in this disclosure refers to a straight or branched chain alkylmoiety having 1 to 8 carbon atoms that is substituted by an aryl groupor a substituted aryl group having 6 to 12 carbon atoms, and includesbenzyl, 2-phenethyl, 2-methylbenzyl, 3-methylbenzyl, 4-methylbenzyl,2,4-dimethylbenzyl, 2-(4-ethylphenyl)ethyl, 3-(3-propylphenyl)propyl.The term “heteroarylcarbonyl” as used in this disclosure refers to aheteroaryl moiety with 5 to 10 membered mono- or fused-heteroaromaticring having at least one heteroatom selected from nitrogen, oxygen andsulfur as mentioned above, and includes, for example, furoyl,nicotinoyl, isonicotinoyl, pyrazolylcarbonyl, imidazolylcarbonyl,pyrimidinylcarbonyl, and benzimidazolyl-carbonyl. Further, “substitutedheteroarylcarbonyl” may refer to the above mentioned heteroarylcarbonylwhich is substituted by at least one substituent selected from halogen,amino, vitro, hydroxy, alkoxy and haloalkyl on the heteroaryl nucleus,and includes, for example, 2-oxo-1,3-dioxolan-4-ylmethyl,2-oxo-1,3-dioxan-5-yl. “Vinyl” refers to an unsaturated substituenthaving at least one unsaturated double bond and having the foimulaCH2═CH—. Accordingly, said “substituted vinyl” may refer to the abovevinyl substituent having at least one of the protons on the terminalcarbon atom replaced with alkyl, cycloalkyl, cycloalkylalkyl, aryl,substituted aryl, heteroaryl or substituted heteroaryl. The term“hydrocarbyl” as used herein refers to a univalent hydrocarbon groupcontaining up to about 24 carbon atoms (i.e. a group containing onlycarbon and hydrogen atoms)and that is devoid of olefinic and acetylenicunsaturation, and includes alkyl, cycloalkyl, alkyl-substitutedcycloalkyl, cycloalkyl-substituted cycloalkyl, cycloalkylalkyl, aryl,alkyl-substituted aryl, cycloalkyl-substituted aryl, arylalkyl,alkyl-substituted aralkyl, and cycloalkyl-substituted aralkyl. Further,functionally-substituted hydrocarbyl groups may refer to a hydrocarbylgroup that is substituted by one or more functional groups selected fromhalogen atoms, amino, nitro, hydroxy, hydrocarbyloxy (including alkoxy,cycloalkyloxy, and aryloxy), hydrocarbylthio (including alkylthio,cycloalkylthio, and arylthio), heteroaryl, substituted heteroaryl,alkanoyl, aroyl, substituted aroyl, heteroarylcarbonyl, and substitutedheteroarylcarbonyl. In some embodiments, hydrogen is replaced by C1I-C6alkyl on atoms not participating in the Pt(II)-S bond. Thehydrophobicity or hydrophilicity of the complex may be adjusted byselecting appropriate substituents for the thione component of thecomplex or by selection of different counteranions or complexingcomponents. A size and relative degree of hydrophilicity orhydrophobicity suitable for a particular mode of administration anduptake of the complex at a desired site of action. For example, acomplex may be made more hydrophobic by substitution of the thionemoiety with alkyl or aryl to increase its ability to cross a lipidbilayer or to interact with non-polar compounds. Alternatively it may bemade more hydrophilic by substitution of the thione moiety with a morepolar substituent to facilitate serum binding, adsorption intowater-containing bodily fluids, or interaction with polar compounds.

Compositions. In many embodiments, the cis-diamine platinum(II)complexes of the invention, the salt thereof, the solvate thereof, aprodrug thereof, or a combination thereof is formulated as apharmaceutically acceptable composition. As used herein, a “composition”refers to a mixture of the active ingredient with at least one otherchemical component, such as a pharmaceutically acceptable carrier orexcipient. One purpose of a composition is to facilitate administrationof the cis-diamine platinum(II) thione complex of the invention, thesalt thereof, the solvate thereof; the prodrug thereof; or a combinationthereof to a subject. Depending on the intended mode of administration(oral, parenteral, or topical), the composition can be in the form ofsolid, semi-solid, liquid, or aerosol dosage forms, such as tablets,suppositories, pills, capsules, powders, liquids, or suspensions,preferably in unit dosage form suitable for single administration of aprecise dosage. The phrase “pharmaceutically acceptable” as used hereinrefers to compounds, counterions, materials, compositions, and/or dosageforms which are, within the scope of sound medical judgment, suitablefor use in contact with the tissues of human beings and animals withoutexcessive toxicity, irritation, allergic response, or other problem orcomplication and commensurate with a reasonable benefit/risk ratio.Therefore, the composition refers to the combination of an activeingredient with a carrier or excipient, inert or active, making thecomposition especially suitable for diagnostic or therapeutic use invivo, ex vivo, or in vitro.

As used herein, a pharmaceutically acceptable carrier refers to acarrier or diluent that does not cause significant irritation to anorganism, does not abrogate the biological activity and properties ofthe administered active ingredient, and/or does not interact in adeleterious manner with the other components of the composition in whichit is contained. The term “carrier” encompasses any excipient, binder,diluent, filler, salt, buffer, solubilizer, lipid, stabilizer, or othermaterial well known in the art for use in pharmaceutical formulations.The choice of a carrier for use in a composition will depend upon theintended route of administration for the composition. The preparation ofpharmaceutically acceptable carriers and formulations containing thesematerials is described in, e.g., Remington's Pharmaceutical Sciences,21st Edition, ed. University of the Sciences in Philadelphia,Lippincott, Williams & Wilkins, Philadelphia Pa., 2005, which isincorporated herein by reference in its entirety. Examples ofphysiologically acceptable carriers include buffers such as phosphatebuffers, citrate buffer, and buffers with other organic acids;antioxidants including ascorbic acid; low molecular weight (less thanabout 10 residues) polypeptides; proteins, such as serum albumin,gelatin, or immunoglobulins; hydrophilic polymers such aspolyvinylpyrrolidone; amino acids such as glycine, glutamine,asparagine, arginine or lysine; monosaccharides, disaccharides, andother carbohydrates including glucose, mannose, or dextrins; chelatingagents such as EDTA; sugar alcohols such as mannitol or sorbitol;salt-foii iing counterions such as sodium; and/or nonionic surfactantssuch as TWEEN® (ICI, Inc.; Bridgewater, N.J.), polyethylene glycol(PEG), and PLURONICS® (BASF; Florham Park, N.J.). An “excipient” refersto an inert substance added to a composition to further facilitateadministration of a compound. Examples, without limitation, ofexcipients include calcium carbonate, calcium phosphate, various sugarsand types of starch, cellulose derivatives, gelatin, vegetable oils, andpolyethylene glycols.

In other embodiments, the composition has various release rates (e.g.controlled release or immediate release). Immediate release refers tothe release of an active ingredient substantially immediately uponadministration. In another embodiment, immediate release occurs whenthere is dissolution of an active ingredient within 1-20 minutes afteradministration. Dissolution can be of all or less than all (e.g., about70%, about 75%, about 80%, about 85%, about 90%, about 91%, about 92%,about 93%, about 94%, about 95%, about 96%, about 97%, about 98%, about99%, about 99.5%, 99.9%, or 99.99%) of the active ingredient, In anotherembodiment, immediate release results in complete or less than completedissolution within about 1 hour following administration. Dissolutioncan be in a subject's stomach and/or intestine. In one embodiment,immediate release results in dissolution of an active ingredient within1-20 minutes after entering the stomach, For example, dissolution of100% of an active ingredient can occur in the prescribed time. Inanother embodiment, immediate release results in complete or less thancomplete dissolution within about 1 hour following rectaladministration. In some embodiments, immediate release is throughinhalation, such that dissolution occurs in a subject's lungs.

Controlled-release or sustained-release refers to the release of anactive ingredient from a composition or dosage form in which the activeingredient is released over an extended period of time. In oneembodiment, controlled-release results in dissolution of an activeingredient within 20-180 minutes after entering the stomach. In anotherembodiment, controlled-release occurs when there is dissolution of anactive ingredient within 20-180 minutes after being swallowed. Inanother embodiment, controlled-release occurs when there is dissolutionof an active ingredient within 20-180 minutes after entering theintestine. In another embodiment, controlled-release results insubstantially complete dissolution after at least 1 hour followingadministration. In another embodiment, controlled-release results insubstantially complete dissolution after at least 1 hour following oraladministration. In another embodiment, controlled-release results insubstantially complete dissolution after at least 1 hour followingrectal administration, . In another embodiment, controlled-releaseresults in substantially complete release of the active component afteror over at least 1, 2, 4, 8, 12, 24 hours or 2, 3, 4, 5, 6, or 7 days(or any intermediate value within this range) following administrationincluding a depot administration into or around a tumor. In oneembodiment, the composition is not a controlled-release composition.

Solid dosage forms for oral administration can include capsules,tablets, pills, powders, and granules. In such solid dosage focus, theactive ingredient is ordinarily combined with one or more adjuvantsappropriate to the indicated route of administration. If administeredper os, the active ingredient can be admixed with lactose, sucrose,starch powder, cellulose esters of alkanoic acids, cellulose alkylesters, talc, stearic acid, magnesium stearate, magnesium oxide, sodiumand calcium salts of phosphoric and sulfuric acids, gelatin, acacia gum,sodium alginate, polyvinylpyrrolidone, and/or polyvinyl alcohol, andthen tableted or encapsulated for convenient administration. Suchcapsules or tablets can contain a controlled-release formulation as canbe provided in a dispersion of active compound in hydroxypropylmethylcellulose. In the case of capsules, tablets, and pills, the dosage formscan also comprise buffering ingredients such as sodium citrate,magnesium or calcium carbonate or bicarbonate. Tablets and pills canadditionally be prepared with enteric coatings.

Liquid dosage forms for oral administration can include pharmaceuticallyacceptable emulsions, solutions, suspensions, syrups, and elixirscontaining inert diluents commonly used in the art, such as water. Suchcompositions can also comprise adjuvants, such as wetting ingredients,emulsifying and suspending ingredients, and sweetening, flavoring, andperfuming ingredients.

For therapeutic purposes, formulations for parenteral administration canbe in the form of aqueous or non-aqueous isotonic sterile injectionsolutions or suspensions. The term “parenteral”, as used herein,includes intravenous, intravesical, intraperitoneal, subcutaneous,intramuscular, intralesional, intracranial, intrapulmonal, intracardial,intrasternal, and sublingual injections, or infusion techniques. Thesesolutions and suspensions can be prepared from sterile powders orgranules having one or nore of the carriers or diluents mentioned foruse in the formulations for oral administration. The active ingredientcan be dissolved in water, polyethylene glycol, propylene glycol,ethanol, corn oil, cottonseed oil, peanut oil, sesame oil, benzylalcohol, sodium chloride, and/or various buffers. Other adjuvants andmodes of administration are well and widely known in the pharmaceuticalart.

Injectable preparations, for example, sterile injectable aqueous oroleaginous suspensions can be formulated according to the known artusing suitable dispersing or wetting ingredients and suspendingingredients. The sterile injectable preparation can also be a sterileinjectable solution or suspension in a non-toxic parenterally acceptablediluent or solvent, for example, as a solution in 1,3-butanediol. Amongthe acceptable vehicles and solvents that can be employed are water,Ringer's solution, and isotonic sodium chloride solution. In addition,sterile, fixed oils are conventionally employed as a solvent orsuspending medium. For this purpose any bland fixed oil can be employedincluding synthetic mono- or diglycerides. In addition, fatty acids,such as oleic acid, find use in the preparation of injectables. Dimethylacetamide, surfactants including ionic and non-ionic detergents,polyethylene glycols can be used. Mixtures of solvents and wettingingredients such as those discussed above are also useful.

Suppositories for rectal administration can be prepared by mixing theactive ingredient with a suitable non-irritating excipient, such ascocoa butter, synthetic mono-, di-, or triglycerides, fatty acids, andpolyethylene glycols that are solid at ordinary temperatures but liquidat the rectal temperature and will therefore melt in the rectum andrelease the drug.

Topical administration can also involve the use of transdermaladministration such as transdermal patches or iontophoresis devices.Formulation of drugs is discussed in, for example, Hoover, John E.,Remington's Pharmaceutical Sciences, Mack Publishing Co., Easton, Pa.,1975. Another example of includes Liberman, H. A. and Lachman, L., Eds.,Pharmaceutical Dosage Forms, Marcel Decker, New York, N.Y., 1980, whichis incorporated herein by reference in its entirety).

Other active ingredients. In some embodiments, other active ingredientsin addition to the cis-diamine platinum(II) thione complex may beincorporated into a composition or separately administered inconjunction with a cis-diamine platinum(II) thione complex. In oneembodiment, the composition is used for treating cancer and furthercomprises a second active ingredient, such as a chemotherapeutic orimmunotherapeutic agent, for the treatment or prevention of neoplasm, oftumor or cancer cell division, growth, proliferation and/or metastasisin the subject; induction of death or apoptosis of tumor and/or cancercells; and/or any other form of proliferative disorder. Exemplarychemotherapeutic agents include, without limitation, aflibercept,asparaginase, bleomycin, busulfan, carmustine, chlorambucil, cladribine,cyclophosphamide, cytarabine, dacarbazine, daunorubicin, doxorubicin,etoposide, fludarabine, gemcitabine, hydroxyurea, idarubicin,ifosfamide, irinotecan, lomustine, mechlorethamine, melphalan,mercaptopurine, methotrexate, mitomycin, mitoxantrone, pentostatin,procarbazine, topotecan, vinblastine, vincristine, retinoic acid,oxaliplatin, carboplatin, 5-fluorouracil, teniposide, amasacrine,docetaxel, paclitaxel, vinorelbine, bortezomib, clofarabine,capecitabine, actinomycin D, epirubicin, vindesine, methotrexate,6-thioguanine, tipifarnib, imatinib, erlotinib, sorafenib, sunitinib,dasatinib, nilotinib, lapatinib, gefitinib, temsirolimus, everolimus,rapamycin, bosutinib, pzopanib, axitinib, neratinib, vatalanib,pazopanib, midostaurin, enzastaurin, trastuzumab, cetuximab,panitumumab, rituximab, bevacizumab, mapatumumab, conatumumab, andlexatumumab. The composition may comprise 0.1-50 wt % of the secondactive ingredient, preferably 10-40 wt %, more preferably 10-20 wt %,relative to the weight of the first active ingredient.

Subjects. The tetins “patient”, “subject”, and “individual” are usedinterchangeably. As used herein, they refer to individuals sufferingfrom a disease, at risk of further progression of a disease, or at riskof acquiring or developing the disease. None of these terms require thatthe individual be under the care and/or supervision of a medicalprofessional.

These terms generally refer to humans, but also apply to mammals, aviansand other animals, especially domesticated or ecologically orcommercially valuable animals. Mammals include non-human primates, suchas chimpanzees, and other apes and monkey species, farm animals, such ascattle, horses, sheep, goats, swine, domestic animals, such as rabbits,dogs, and cats, laboratory animals including rodents, such as rats, miceand guinea pigs, and the like. In a preferred embodiment, the subject isa human.

A subject in need of treatment includes a subject already with a diseasesuch as cancer, a subject who does not yet experience or exhibitsymptoms of the disease, and a subject who is predisposed to the diseasefor example based on family history or genetic profile. In preferredembodiments, the subject is a person who is predisposed to cancer suchas a person with a family history of cancer. In another embodiment, thesubject refers to a cancer patient who has been previouslyadministered/treated with cisplatin and have cisplatin resistance, forexample in the form of high ERCC1 mRNA levels, overexpression ofHER-2/neu, activation of the PI3-K/Akt pathway, loss of p53 function,and/or overexpression of antiapoptotic bc1-2).

The term active ingredient, as used herein, refers to an ingredient inthe composition that is biologically active, for example, thecis-diamine platinum(II) complexes disclosed herein, a salt thereof, aprodrug thereof or a solvate thereof. Other active ingredients include,but are not limited to, those that exert a substantial pharmacokineticor pharmacodynamic activity when in admixture with a cis-diamineplatinum(II) thione complex, for example, other anti-cancer drugs,immunopotentiators, or other agents.

Antitumor properties may be evaluated by methods known in the art,including these described by and incorporated by reference to Y. F. To,R. W.-Y. Sun, Y. Chen, V. S.-F. Chan, W.-Y. Yu, P. K.-H. Tam, C.-M. Cheand C.-L. S. Lin, Int. J. Cancer, 2009, 124, 1971-1979; C. I. Lum, Z. F.Yang, H. Y. Li, R. W.-Y. Sun, S. T. Fan, R. T. P. Poon, M. C. M. Lin,C.-M. Che and H. F. Kung, Int. J. Cancer, 2006, 118, 1527-1538; C. T.Lum, A. S.-T. Wong, M. C. M. Lin, C.-M. Che and R. W.-Y. Sun, Chem.Commun., 2013, 49, 4364-4366; C.-M. Che, R. W.-Y. Sun, W.-Y. Yu, C.-B.Ko, N. Zhu and H. Sun, Chem. Comtn n., 2003, 1718-1719; Y. Wang, Q.-Y.He, R. W.-Y. Sun, C.-M. Che and J.-F. Chiu, Eur. J. Pharmacol., 2007,554, 113-122—each incorporated by reference.

Cytotoxic activity. In one embodiment, the IC₅₀ of the platinum(II)complexes is in a range of 0.01-200 μM, 0.1-100 μM, 1-100 μM, 10-90 μM,20-80 μM, 30-80 μM, 40-80 μM, 50-80 μM, or 50-75 μM. These rangesinclude all intermediate subranges and values. As used herein, the term“IC₅₀” refers to a concentration of a platinum(II) complex, the saltthereof, the prodrug thereof, or the solvate thereof, which causes thedeath of 50% of cancer or proliferating cells in 72 hours (3 days) suchas the A549 (human lung carcinoma), MCF-7 (human breast carcinoma) andHTC15 (human colon cancer) cell lines described herein. The IC₅₀ can bedetermined by standard cell viability assays, such as, withoutlimitation, ATP test, calcein AM assay, clonogenic assay, ethidiumhomodimer assay, Evans blue assay, Fluorescein diacetatehydrolysis/propidium iodide staining assay, flow cytometry assay,formazan-based assays (MTT, XTT), green fluorescent protein assay,lactate dehydrogenase assay, methyl violet assay, propidium iodideassay, Resazurin assay, Trypan Blue assay and TUNEL assay. Preferably, aMTT assay and/or a Trypan Blue assay is used.

While not being bound to any particular explanation, it is believed thatinteraction of the complexes of the invention with polynucleotidesaccount for cytotoxic activity. As shown by FIG. 3C, the N7 atoms of theimidazole rings in the DNA purine bases guanine and adenine are mostnucleophic and accessible site which can be a major target forplatination. After the binding of platinum to the nucleophilic site N7of guanine and adenine, the ammine ligands act as hydrogen-bond donors,whereas C6 position in the guanine ring (oxo group) and (amino group) inthe case of adenine ring, known to be hydrogen-bond acceptors. Thishydrogen bond, especially between the N—H . . . O═C6 in case of guanine,is a factor in the stabilization of the Pt-DNA adduct. Moreover, it isbelieved that the N7 atoms of the imidazole rings in the DNA purinebases guanine and adenine is most nucleophic and accessible site whichcan be a major target for platination. After the binding of platinum tothe nucleophilic site N7 of guanine and adenine, the amine ligands actas hydrogen-bond donors, whereas C6 position in the guanine ring (oxogroup) and (amino group) in case of adenine ring, known to behydrogen-bond acceptors. This hydrogen bond especially between the N—H .. . O═C6 in case of guanine is a factor in the stabilization of thePt-DNA adduct.[

Nephrotoxicity. Cisplatin is known to be nephrotoxic. Nephrotoxicity ofcisplatin or other anticancer drugs may be evaluated by comparison withthe Pt(II) thione complexes of the invention by known methods such asevaluation of nephrotoxicity through blood tests including a measurementof blood urea nitrogen (BUN), concentration of serum creatinine,glomerular Filtration rate and/or creatinine clearance. Other methodsmay also be used to assess absolute or relative nephrotoxicity such asthose described by Kim, et al., Drug-Induced Nephrotoxicity and ItsBiomarkers, Biomol Ther (Seoul). 2012 May; 20(3): 268-272, see the textat www.ncbi.nlm.nih.gov/pmc/articles/PMC3794522/(last accessed Oct. 19,2017, incorporated by reference). In some embodiments, a cis-diaminePt(II) thione complex of the invention will not exhibit substantialnephrotoxicity or will exhibit 10, 20, 30, 40, 50, 60, 70, 80, 90, or95% of the nephrotoxicity of cisplatin or other anticancer drug based onequivalent dosage or on equivalent effective dosages.

Neurotoxicity. Neurotoxicity is toxicity in the nervous system. Itoccurs when exposure to natural or artificial toxic substances, whichare called neurotoxins, alters the normal activity of the nervous systemin such a way as to cause damage to nervous tissue. This can eventuallydisrupt or even kill neurons, key cells that transmit and processsignals in the brain and other parts of the nervous system.Neurotoxicity can result from exposure to substances used inchemotherapy, radiation treatment, drug therapies, certain drug abuse,and organ transplants, as well as exposure to heavy metals, certainfoods and food additives, pesticides, industrial and/or cleaningsolvents, cosmetics, and some naturally occurring substances. Symptomsmay appear immediately after exposure or be delayed. They may includelimb weakness or numbness, loss of memory, vision, and/or intellect,uncontrollable obsessive and/or compulsive behaviors, delusions,headache, cognitive and behavioral problems and sexual dysfunction.Individuals with certain disorders may be especially vulnerable toneurotoxins.

Cisplatin, carboplatin, and oxaliplatin anticancer drugs are commonlyused to treat lung, colorectal, ovarian, breast, head and neck, andgenitourinary cancers. However, the efficacy of platinum-based drugs isoften compromised because of the substantial risk for severe toxicities,including neurotoxicity. Neurotoxicity can result in both acute andchronic debilitation. Moreover, colorectal cancer patients treated withoxaliplatin discontinue therapy more often because of peripheralneuropathy than tumor progression, potentially compromising patientbenefit.

Neurotoxicity may be diagnosed by methods known in the art including bytoxicological and neurological testing such as those described byMcWhinney, et al., Mol Cancer Ther Jan. 1 2009 (8) (1) 10-16; DOI:10.1158/1535-7163.MCT-08-0840, Platinum neurotoxicity pharmacogeneticshereby incorporated by reference. In some embodiments, a cis-diaminePt(II) complex of the invention will not produce substantialneurotoxicity or will exhibit 10, 20, 30, 40, 50, 60, 70, 80, 90, or 95%of the neurotoxicity of cisplatin or other anticancer drug based onequivalent dosages or on equivalent effective dosages.

Biomarkers. Alternatively to use of IC₅₀ values, efficacy of treatmentwith a platinum(II) complex of the invention may be determined bymeasuring or detecting a change in one or cancer biomarkers, forexample, comparing quantity of hiomarkers in a blood or tissue samplebefore and after a treatment.

A treatment may significantly decrease the concentration of a particularbiomarker, for example, by 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55,60, 65, 70, 75, 80, 85, 90, or 100%, compared to a control orpre-treatment value. As used herein, the term “biomarker” refers to acharacteristic that is objectively measured and evaluated as anindicator of normal biological processes, pathogenic processes orpharmacological responses to a therapeutic intervention. Biomarkersinclude ER/PR, HER-2/neu for breast cancer, EGFR, KRAS, UGT1A1 forcolorectal cancer, EML4/ALK, EGFR, and KRAS for lung cancer as well asother biomarkers described and incorporated by reference tohaps://_en.wikipedia.org/wiki/Cancer_biomarkers (last accessed Oct. 5,2017). Cancer biomarkers are useful in determining the aggressiveness ofan identified cancer as well as its likelihood of responding to thetreatment. Examples of such prognostic biomarkers include, withoutlimitation, CA125, β2-microglobulin, and EBV DNA. A change or mutationin a biomarker may be detected with a polymerase chain reaction (PCR)assay, DNA microarray, multiplex ligation-dependent probe amplification(MLPA), single strand conformational polymorphism (SSCP), denaturinggradient gel electrophoresis (DGGE), heteroduplex analysis, andrestriction fragment length polymorphism (RFLP). The procedures todetect the mutation are well-known to those of ordinary skill in theart. The concentration of the biomarker may he measured with an assay,for example an antibody-based method (e.g., an ELISA). As used herein,the term antibody-based method refers to any method with the use of anantibody including, but not limited to, enzyme-linked immunosorbentassay (ELISA), Western blotting, immunoprecipitation (IP), enzyme linkedimmunospot (ELISPOT), immunostaining, immunohistochemistry,immunocytochemistry, affinity chromatography, and the like. Preferably,an ELISA is used. The term ELISA refers to a method of detecting thepresence and concentration of a biomarker in a sample, for example,before, during or after treatment with a cis-diamine Pt(II) thionecomplex of the invention. There are several variants of ELISA,including, but not limited to, sandwich ELISA, competitive ELISA,indirect ELISA, ELISA reverse, and the like. The ELISA assay may be asingleplex assay or a multiplex assay, which refers to a type of assaythat simultaneously measures multiple analytes in a single run/cycle ofthe assay. Preferably, a sandwich ELISA is used. The protocol formeasuring the concentration of the biomarker and/or detecting themutation in the biomarker is known to those of ordinary skill, forexample by performing the steps outlined in the commercially availableassay kit sold by Sigma-Aldrich, Thermo Fisher Scientific, R & DSystems, ZeptoMetrix Inc., Cayman Inc., Abeam, Trevigen, DojindoMolecular Technologies, Biovision, and Enzo Life Sciences. The termsample includes any biological sample taken from the subject including acell, tissue sample, or body fluid. For example, a sample may include atumor sample, skin sample, a cheek cell sample, saliva, or blood cells.A sample can include, without limitation, a single cell, multiple cells,fragments of cells, an aliquot of a body fluid, whole blood, platelets,serum, plasma, red blood cells, white blood cells, endothelial cells,tissue biopsies, synovial fluid, and lymphatic fluid. In someembodiments, the sample is taken from a tumor. In some embodiments, theconcentration of the biomarker is measured before and after theadministration. When the concentration of the biomarker is maintained,the method may further comprise increasing the effective amount of atleast one of the cis-diamine platinum(II) complex of the invention, thesalt thereof, the solvate thereof, the prodrug thereof, and thecombination thereof by at least 5%, at least 10%, or at least 30%, up to50%, up to 60%, or up to 80% of an initial effective amount that is in arange of 1-100 mg/kg based on the weight of the subject. The subject maybe administered with the increased dosage for a longer period (e.g. 1week more, 2 weeks more, or 2 months more) than the duration with theinitial effective amount. In some embodiments, the mutation in thebiomarker is detected before administrating the composition to identifysubjects predisposed to the disease. For example, women with a BRCA1germline mutation are at a higher risk of contracting ovarian cancer. Insome embodiments, the biomarkers are measured/detected after eachadministration. For example, the measurement may be 1-5 minutes, 1-30minutes, 30-60 minutes, 1-2 hours, 2-12 hours, 12-24 hours, 1-2 days,1-15 weeks, 15-20 weeks, 20-30 weeks, 30-40 weeks, 40-50 weeks, 1 year,2 years, or any period of time in between after the administration.

Cancers/Proliferative Disorders. Cancers include but are not limited tosarcomas, carcinomas, melanomas, myelornas, gliomas and lymphoma(including Bodkin lymphoma) subject to treatment or prevention with thecis-diamine platinum(II) thione complexes provided herein. In someembodiments, the cis-diamine Pt(II) thione complexes of the inventionretain anti-cancer activity against cancer cells that are or have becomeresistant to conventional anti-cancer drugs such as cisplatin. Whenresistance develops to a conventional anticancer drug, treatment may becontinued with a cis-diamine Pt(II) thione complex of the invention towhich the cancer cells are sensitive. Sensitivity of a particular kindof cancer or proliferative disease, disorder or condition to aparticular cis-diamine Pt(II) thione complex may be determined bymethods known in the art.

In some embodiments, methods incorporating the use a cis-diamineplatinum(II) thione complex of the present disclosure to treat orprevent cancer of the blood, brain, bladder, lung, cervix, ovary, colon,rectum, pancreas, skin, prostate gland, stomach, breast, liver, spleen,kidney, head, neck, testicle, bone, bone marrow, thyroid gland orcentral nervous system. In some embodiments, these methods are effectivein the treatment or prevention of cervical, colon, prostate, and lungcancers. Cancers or tumor resistant to other anticancer drugs, such ascisplatin-resistant cancers, may be treated. In treating certaincancers, the best approach is often a combination of surgery,radiotherapy, and/or chemotherapy. Therefore, in at least oneembodiment, the composition is employed in conjunction with conventionalradiotherapy and/or chemotherapy. In another embodiment, the compositionis employed with surgery. The radiotherapy and/or surgery may be beforeor after the composition is administered.

Other non-cancerous proliferative diseases, disorders or conditions mayalso be treated, such as atherosclerosis, rheumatoid arthritis,psoriasis, idiopathic pulmonary fibrosis, scleroderma, cirrhosis of theliver, or benign proliferative conditions such as verruca (warts),dermatitis, or other disorders characterized by epidemial cellproliferation.

Colon cancer, bowel cancer, or colorectal cancer develops and manifestsin the colon and rectum which are parts of the large intestine. Coloncancers represent abnormal growth of cells that have the ability toinvade or spread to other parts of the body. Signs and symptoms mayinclude blood in the stool, a change in bowel movements, weight loss,and feeling tired all the time. Most colorectal cancers are associatedwith old age and can occur in subjects 50, 55, 60, 65, 70, 75, 80 ormore years of age. Colon cancer is also associated with lifestylefactors and some cases are associated with genetic risks. Risk factorsinclude diet, obesity, smoking, and lack of physical activity. Dietaryfactors that increase the risk include red and processed meat as well asalcohol. Another risk factor is inflammatory bowel disease, whichincludes Crohn's disease and ulcerative colitis. Some of the inheritedgenetic disorders that can cause colorectal cancer include familialadenomatous polyposis and hereditary non-polyposis colon cancer. Coloncancer often starts as a benigm tumor, often in the form of a polyp,which over time becomes cancerous. The most common metastasis sites forcolorectal cancer are the liver, the lung and the peritoneum. Treatmentsused for colorectal cancer may often include a combination of surgery,radiation therapy, chemotherapy and targeted therapy.

Lung cancer or lung carcinoma is a malignant lung tumor characterized byuncontrolled cell growth in tissues of the lung and can metastasize tonearby and distant tissues. Most cancers that start in the lung, knownas primary lung cancers, are carcinomas and the two main types aresmall-cell lung carcinoma (SCLC) and non-small-cell lung carcinoma(NSCLC). The most common symptoms are coughing (including coughing upblood), weight loss, shortness of breath, and chest pains. The vastmajority (85%) of cases of lung cancer are due to long-term tobaccosmoking, however some cases are associated with or caused by combinationof genetic factors and exposure to environmental factors such as radongas, asbestos, second-hand smoke, or other forms of air pollution. Lungcancer may be seen on chest radiographs and computed tomography (CT)scans and diagnosis is usually confirmed by biopsy which is usuallyperformed by bronchoscopy or CT-guidance. Common treatments includesurgery, chemotherapy, and radiotherapy. NSCLC is sometimes treated withsurgery, whereas SCLC usually responds better to chemotherapy andradiotherapy.

Breast cancer is cancer that develops from breast tissue. Signs ofbreast cancer may include a lump in the breast, a change in breastshape, dimpling of the skin, fluid coming from the nipple, or a redscaly patch of skin In breast cancers with distant spread of thedisease, there may be bone pain, swollen lymph nodes, shortness ofbreath, or yellow skin. Risk factors for developing breast cancerinclude being female, obesity, lack of physical exercise, drinkingalcohol, hormone replacement therapy during menopause, ionizingradiation, early age at first menstruation, having children late or notat all, older age, and family history. About 5-10% of cases are due togenes inherited from a person's parents, including BRCA1 and BRCA2 amongothers. The cis-diamine Pt(II) thione complex of the invention may beadministered by itself or in combination with other therapy to a subjectat risk of breast cancer, a subject diagnosed with breast cancer, or asubject under treatment for breast cancer, or a subject who has alreadybeen treated for breast cancer, for example, by removal of breasttissue.

Therapy. As used herein, the terms “therapies” and “therapy” can referto any method, composition, and/or active ingredient that can be used inthe treatment and/or management of the disease or one or more symptomsthereof In some embodiments, the method for treating the diseaseinvolves the administration of a unit dosage or a therapeuticallyeffective amount of the active ingredient to a subject in need thereof.

Administration. The terms “administer”, “administering”,“administration”, and the like, as used herein, refer to the methodsthat may be used to enable delivery of the active ingredient and/or thecomposition to the desired site of biological action. Routes or modes ofadministration are as set forth herein. These methods include, but arenot limited to, oral routes, intraduodenal routes, parenteral injectionincluding intravenous, subcutaneous, intraperitoneal, intramuscular,intravascular, or infusion, topical and rectal administration. Those ofordinary skill in the art are familiar with administration techniquesthat can be employed with the compounds and methods described herein. Inpreferred embodiments, the active ingredient and/or the compositiondescribed herein are administered orally.

The terms “effective amount”, “therapeutically effective amount”, or“pharmaceutically effective amount” refer to that amount of the activeingredient being administered which will relieve to some extent one ormore of the symptoms of the disease being treated. The result can bereduction and/or alleviation of the signs, symptoms, or causes of adisease, or any other desired alteration of a biological system. Forexample, an “effective amount” for therapeutic uses is the amount of thecis-diamine platinum(II) complex of the invention, the salt thereof, thesolvate thereof, the prodrug thereof, or a combination thereof asdisclosed herein required to provide a clinically significant decreasein a disease. An appropriate “effective amount” may differ from oneindividual to another. An appropriate “effective amount” in anyindividual case may be determined using techniques, such as a doseescalation study.

The dosage and treatment duration are dependent on factors, such asbioavailability of a drug, administration mode, toxicity of a drug,gender, age, lifestyle, body weight, the use of other drugs and dietarysupplements, the disease stage, or tolerance and resistance of the bodyto the administered drug, and then determined and adjusted accordingly.In at least one embodiment, the at least one of the cis-diamineplatinum(II) complex of the invention, the salt thereof, the solvatethereof, the prodrug thereof, and the combination thereof isadministered in an effective amount in a range of 1-100 mg/kg based onthe weight of the subject, preferably 10-80 mg/kg, more preferably 20-50mg/kg.

In some embodiments, a treatment will involve administering acomposition comprising at least 0.5 wt %, 5 wt %, 10 wt %, 15 wt %, 20wt %, 25 wt %, 30 wt %, 35 wt %, 40 wt %, 45 wt %, 50 wt %, 55 wt ° A,60 wt %, 65 wt %, 70 wt %, 75 wt %, 80 wt %, 85 wt %, 90 wt 95 wt %, 99wt %, or 99.9 wt %, of the cis-diamine platinum(II) complex of theinvention. The composition may comprise 0.01-50 μM, 0.01-30 μM,preferably 0.01-10 μM of the cis-diamine platinum(II) thione complex ofthe invention relative to the total composition. In some embodiments,the composition comprises up to 0.1 wt %, 1 wt %, 5 wt %, or 10 wt % ofthe pharmaceutically acceptable salt of the cis-diamine platinum(II)thione complex of the invention. In some embodiments, the compositioncomprises up to 0.1 wt %, 1 wt %, 5 wt %, or 10 wt % of thepharmaceutically acceptable solvate thereof of either the cis-diamineplatinum(II) complex of the invention. These ranges include allintermediate subranges and values.

A treatment method may comprise administering a composition containingthe cis-diamine platinum(II) thione complex of the invention as a singledose or multiple individual divided doses. In some embodiments, thecomposition is administered at various dosages (e.g., a first dose withan effective amount of 50 mg/kg and a second dose with an effectiveamount of 10 mg/kg). In some embodiments, the interval of time betweenthe administration of the composition and the administration of one ormore additional therapies may be about 1-5 minutes, 1-30 minutes, 30minutes to 60 minutes, 1 hour, 1-2 hours, 2-6 hours, 2-12 hours, 12-24hours, 1-2 days, 2 days, 3 days, 4 days, 5 days, 6 days, 7 days, 1 week,2 weeks, 3 weeks, 4 weeks, 5 weeks, 6 weeks, 7 weeks, 8 weeks, 9 weeks,10 weeks, 15 weeks, 20 weeks, 26 weeks, 52 weeks, 11-15 weeks, 15-20weeks, 20-30 weeks, 30-40 weeks, 40-50 weeks, 1 month, 2 months, 3months, 4 months, 5 months, 6 months, 7 months, 8 months, 9 months, 10months, 11 months, 12 months, 1 year, 2 years, or any period of time inbetween. Preferably, the composition is administered once daily for atleast 2 days, 5 days, 6 days, or 7 days. In certain embodiments, thecomposition and one or more additional therapies are administered lessthan 1 day, 1 week, 2 weeks, 3 weeks, 4 weeks, one month, 2 months, 3months, 6 months, 1 year, 2 years, or 5 years apart.

Embodiments

The following examples illustrate various aspects of the presentinvention. They are not to be construed to limit the claims in anymanner whatsoever.

-   1. A method for treating a proliferative disease, disorder, or    condition comprising administering to a subject in need thereof a    complex comprising the formula [Pt(N R₁R₂)₂(Thione)₂].2[anion];    wherein R₁ and R₂ are, independently, hydrogen, alkyl or aryl.-   2. The method of embodiment I, wherein the thione molecule used to    produce the complex is selected from the group consisting of:

wherein. R, independently, is H, alkyl, or aryl which may be furthersubstituted.

-   3. The method of embodiment 1, wherein the thione molecule used to    produce the complex is selected from the group consisting of:

wherein in (a) R═R′═H; (b) R═H, R′═CH₃; (c) R═CH₃, R^(/)═CH₃; (d)R═R′═C₂H₅; (e) R═H, R′═C₃H₇; (f) R═H, R′=i-C₃H₇; (g) R═R′=i-C₃H₇; (h)R═H; (i) R═C₂H₅; and (j) is 1,3-Diazepane-2-thione (Diap).

-   4. The method of embodiment 1, wherein the platinum (II) complex has    the formula Pt(NH₃)₂(Thione)₂].2NO₃ or a variant complex wherein one    or two of the NO₃ anions are replaced with one or more different    anions.-   5. The method of embodiment 1, wherein the complex is selected from    the group consisting of at least one of cis-[Pt(NH₃)₂(Imt)₂].2NO₃    (1), cis-[Pt(NH₃)₂(MeImt)₂].2NO₃ (2), cis-[Pt(NH₃)₂(Me₂Imt)₂].2NO₃    (3), cis-[Pt(NH₃)₂(Et₂Imt)₂].2NO₃ (4), cis-[Pt(NH₃)₂(PrImt)₂].2NO₃    (5), cis-[Pt(NH₃)₂(iPrImt)₂].2NO₃ (6), cis-[Pt(NH₃)₂(iPr₂Imt)₂].2NO₃    (7), cis-[Pt(NH₃)₂(Diaz)₂].2NO₃ (8), cis-[Pt(NH₃)₂(EtDiaz)₂].2NO₃    (9), and cis-[Pt(NH₃)₂(Diap)₂].2NO₃ (10), or a variant complex    wherein one or two of the NO₃ anions are replaced with one or more    different anions,-   6. The method of embodiment 5, wherein in said cis-diamine    platinum(II) thione complex both anions are NO₃.-   7. The method of embodiment 1, wherein the proliferative disease,    disorder or condition is cancer.-   8. The method of embodiment 1, wherein the proliferative disease,    disorder or condition is not cancer.-   9. The method of claim 1, wherein the proliferative disease,    disorder or condition is cancer that is or has become resistant to    cisplatin or wherein the cis-diamine Pt(II) thione complex produces    less nephrotoxicity or neurotoxicity that the same dose of    cisplatin.-   10. The method of embodiment 1, wherein the proliferative disease,    disorder, or condition is breast cancer.-   11. The method of embodiment 1, wherein the proliferative disease,    disorder, or condition is colon cancer.-   12. The method of embodiment 1, wherein the proliferative disease,    disorder, or condition is lung cancer.-   13. A cis-diamine platinum(II) thione complex comprising the formula    [Pt(N R₁R₂)₂(Thione)₂].2[anion]; wherein R₁ and R₂ are,    independently, hydrogen, alkyl or aryl.-   14. The cis-diamine platinum(II) thione complex of embodiment 12,    wherein the thione molecule used to produce the complex is selected    from the group consisting of:

wherein R, independently, is H, alkyl, or aryl.

-   15. The cis-diamine platinum(II) thione complex of embodiment 14,    wherein the thione molecule used to produce the complex is selected    from the group consisting of:

wherein in (a) R═R′═H; (b) R═H, R′═CH₃; (c) R═CH₃, R^(/)═CH₃; (d)R═R′═C₂H₅; (e) R═H, R′═C₃H₇; (f) R═H, R′=i-C₃H₇; (g) R═R′=i-C₃H₇; (h)R═H; (i) R═C₂H₅; and (j) is 1,3-Diazepane-2-thione (Diap).

-   16. The cis-diamine platinum(II) thione complex of embodiment 14,    wherein the platinum (II) complex has the formula    Pt(NH₃)₂(Thione)₂].2NO₃ or a variant complex wherein one or two of    the NO₃ anions are replaced with one or more different anions. 17.    The cis-diamine platinum(II) thione complex of embodiment 14,    wherein the complex is selected from the group consisting of at    least one of cis-[Pt(NH₃)₂(Imt)₂].2NO₃ (1),    cis-[Pt(NH₃)₂(MeImt)₂].2NO₃ (2), cis-[Pt(NH₃)₂(Me₂Imt)₂].2NO₃ (3),    cis-[Pt(NH₃)₂(Et₂Imt)₂].2NO₃ (4), cis-[Pt(NH₃)₂(PrImt)₂].2NO₃ (5),    cis-[Pt(NH₃)₂(iPrImt)₂].2NO₃ (6), cis-[Pt(NH₃)₂(iPr₂Imt)₂].2NO₃ (7),    cis-[Pt(NH₃)₂(Diaz)₂].2NO₃ (8), cis-[Pt(NH₃)₂(EtDiaz)₂].2NO₃ (9),    and cis-[Pt(NH₃)₂(Diap)₂].2NO₃ (10), or a variant complex wherein    one or two of the NO₃ anions are replaced with one or more different    anions.-   18. The cis-diamine platinum(II) thione complex of embodiment 14 ,    wherein both anions are NO_(3.)-   19. A pharmaceutical composition comprising at least one cis-diamine    platinum(II) thione complex of embodiment 13 in combination with at    least one pharmaceutically acceptable carrier or excipient.-   20. The pharmaceutical composition of embodiment 19 that further    comprises another anticancer drug, chemotherapeutic agent, or    immunopotentiator.

EXAMPLES Example 1 Synthesis of cis-[Pt(NH₃)₂L₂].2NO₃ compleses (1-10)

Cisplatin was obtained from Strem Chemical Company, USA.Dimethylsulfoxide-d₆ and D₂O were purchased from Fluka Chemical Co. Thethione ligands were prepared according to the procedure mentioned in theliterature. See S. Ahmad, A. A. Isab, H. P. Perzanowski. Can. J. Chem.80 (2002) 1279-1284; and A. A. Isab, S. Ahmad, M. Arab, Polyhedron 21(2002)1267-1271, each incorporated herein by reference in theirentirety. (3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide,a yellow tetrazole) was purchased from Sigma Chemical Co, St. Louis,Mo., USA.

Compounds 1-10 were prepared by adding 0.17 g (1.0 mmol) AgNO₃ to thesolutions containing (0.15g, 0.5 mmol) ofcis-diaminedichloridoplatinum(II) (cisplatin) in 10 mL water andstirring the mixture for one hour in the dark at room temperature. Thesolution was filtered to remove silver chloride as solid. Then 1.0 mmolof thione ligands dissolved in 10 mL methanol was added to the filtratesdropw se. After stirring the solution for one hour it was filtered andkept at room temperature, Solid powders were obtained on slowevaporation of the solvent. The CHNS data, melting/decomposition points,and % yield of the synthesized complexes are presented below:

cis-[Pt(NH₃)₂(Imt)₂].2NO₃ (1): M. p, 130-132° C.; Yield 0.248g, 89%;Analysis. Calc.: C 12.93%, H 3.25%, N 20.10, S 11,50%; Found: C 12,48%,H 3.56%, N 20.26%, S 11.37%. IR (v, cm⁻¹): 3376 (s), 1036 (s), 494 (s),827 (δ, s), 273 (s).

cis-[Pt(NH₃)₂(MeImt)₂].2NO₃ (2): M. p. 126-128° C.; Yield 0.213g, 73%;Analysis. Calc.: C 16.41%, H 3.79%, N 19.14, S 10.95%; Found: C 16.46%,H 3.73%, N 19.06%, S 11.06%. IR (v, cm⁻¹): 3481 (s), 1028 (s), 501 (s),823 (δ, s), 287 (s).

cis-[Pt(NH₃)₂(Me₂Imt)₂].2NO₃ (3): M. p. 73-75° C.; Yield 0.214g, 70%;Analysis. Calc.: C 19.57%, H 4.27%, N 18.16, 5 10.45%; Found: C 19.41%,H 4.22%, N 18.10%, 5 10.34%. IR (v, cm⁻¹): 1118 (s), 491 (s), 825 (δ,s), 280 (s).

cis-[Pt(NH₃)₂(Et₂Imt)₂].2NO₃ (4): M. p. 111-113° C.; Yield 0.211g, 64%;Analysis. Calc.: C 25.11%, H 5.12%, N 16.73, S 9.58%; Found; C 25.41%, H5.22%, N 16.97%, S 9.84%, IR (v, cm⁻¹): 1079 (s), 492 (s), 837 (δ, s),268 (s).

cis-[Pt(NH₃)₂(PrImt)₂].2NO₃ (5): M. p. 125-127° C.; Yield 0.231g, 72%;Analysis. Calc.: C 22.46%, H 4.71%, N 17.48, S 9.99%; Found: C 22.04%, H4.88%, N 17.21%, S 10.07%. IR (v, cm⁻¹): 3462 (s), 1048 (s), 501 (s),827 (δ, s), 282 (s).

cis-[Pt(NH₃)₂(iPrImt)₂].2NO₃ (6): M. p. 138-140° C.; Yield 0.263g, 82%;Analysis. Calc.: C 22.46%, H 4.71%, N 17.48, S 9.99%; Found: C 21.99%, H4.49%, N 17.35%, S 9.62%. IR (v, cm⁻¹): 1078 (s), 508 (s), 840 (δ, s),283 (s).

cis-[Pt(NH₃)₂(iPr₂Imt)₂].2NO₃ (7): M. p. 119-121° C.; Yield 0.178g, 49%;Analysis. Calc.: C 29.79%, H 5.83%, N 15.44, S 8.84%; Found: C 29.29%, H5.62%, N 15.65%, S 8.77%. IR (v, cm⁻¹): 1062 (s), 520 (s), 824 (δ, s),274 (s).

cis-[Pt(NH₃)₂(Diaz)₂].2NO₃ (8): M. p. 112-114° C.; Yield 0.254g, 87%;Analysis. Calc.: C 16.41%, H 3.79%, N 19.14, S 10.95%; Found: C 16.78%,H 3.92%, N 19.45%, S 10.89%. IR (v, cm⁻¹): 3459 (s), 1070 (s), 507 (s),811 (δ, s), 268 (s).

cis-[Pt(NH₃)₂(EtDiaz)₂].2NO₃ (9): M. p. 86-88° C.; Yield 0.211g, 66%;Analysis. Calc.: C 22.46%, H 4.71%, N 17.48, S 9.99%, Found: C 22.32%, H4.47%, N 17.53%, 5 9.68%. IR (v, cm⁻¹): 3428(s), 1121 (s), 499 (s), 827(δ, s), 291 (s).

cis-[Pt(NH₃)₂(Diap)₂].2NO₃ (10): M. p. 155-157° C.; Yield 0.274, 89%;Analysis. Calc.: C 19.57%, 1-1 4.27%, N 18.26, S 10.45%, Found: C18.89%, 11 4.34%, N 18.67%, S 10.49%. IR (v, cm⁻¹): 3237(s), 1066 (s),502 (s), 824 (δ, s), 276 (s).

Synthesis. For the preparation of complexes, cisplatin was firstconverted into nitrate form by addition of two equivalents of AgNO₃ tocisplatin. The nitrate species was then reacted with thione (L) ligandsin a 1:2 molar ratio. The reaction yielded the colored complexes of thegeneral formula, cis-[Pt(NH₃)₂(L)₂].2NO₃ in high yields. The observedvalues of elemental (CHNS) analysis of these complexes are consistentwith the suggested compositions.

Example 2 Spectroscopic Measurements

Elemental analysis of carbon, hydrogen, nitrogen and sulfur wereperformed on Perkin Elmer Series 11 (CHNS/O), Analyzer 2400. The solidstate FTIR spectra of the ligands and their platinum(II) complexes wererecorded on a NICOLET 6700 FTIR using diamond ATR over the range4000-400 cm⁻¹.

The ¹H and ¹³C NMR spectra in DMSO-d₆ and D₂O were carried out on a JEOLJNM-LA 500 NMR spectrometer at 500.00 MHz and 125.65 MHz operatingfrequency respectively. The ¹³C NMR spectra were recorded with ¹Hbroadband decoupling at 297 K. The conditions of the spectral were 32 Kdata points, 0.963 acquisition time, 3.2 s pulse delay and a 5.75 μspulse width for ¹H NMR, and 32 K data points, 0.963 s acquisition time,2.5 s pulse delay and a 5.12 μs pulse width for ¹³C NMR. The chemicalshifts were measured relative to Tetramethylsilane (TMS).

IR spectroscopy. The selected Infrared absorption frequencies of thefree ligands and their platinum(II) compounds are listed in Table S1.Three characteristic vibrational bands are usually observed in the IRspectra of thione complexes, which include, v(C═S) vibration, whichoccurs around 1200 and 600 cm⁻¹, the N—H stretching near 3200 cm⁻¹ andM-sulfur stretching band. The presence of v(N—H) and v(C═S) bands in allcomplexes prove the presence of thione ligands in the complexes in thesolid state. The spectra of all free ligands display a band around 600cm⁻¹ as well as 1200 cm⁻¹ that belong to v(C═S) stretching. See, S.Ahmad et al.; A. A. Isab et al.; and B. P. Kennedy, A. B. P. Lever, Can.J. Chem. 50 (1972) 3488-3507, each incorporated herein by reference intheir entirety. These bands shifted toward lower wave number uponcomplexation in agreement with our suggestion that sulfur atom is bondedto metal centre and the double bond character of C═S bond has beenreduced. In order to investigate metal-sulfur stretching frequencies ofthe synthesized complexes, the spectra were recorded in the far-infraredregion below 400 cm⁻¹, This band lies in the range of about 300 cm⁻¹ forthe transition-metal complexes according to the literature. See D. M,Adam, J. B. Cornell. J. Chem. Soc. (1967) 884-889, incorporated hereinby reference in its entirety. In all complexes, we observed a sharp peakaround 280 cm⁻¹ that was assigned to platinum-sulfur bond.

A sharp band around 825 cm⁻¹ for all cis-[Pt(NH₃)₂(L)₂].2NO₃ complexesand its absence in the free ligand spectra is attributed to the presenceof non-coordinated nitrate ion. See A. A. Isab et al., incorporatedherein by reference in its entirety.

¹H and ¹³C NMR Spectroscopy. All the signals of thione ligands detectedin the ¹H and ¹³C NMR spectra of uncomplexed molecules were also foundin the spectra of the Pt(II) complexes, which are summarized in Tables 1and 2 respectively. Upon coordination, the N—H signal of thiones becomeless intense and shifted upfield by 0.64-1.14 ppm with respect to theirpositions in free ligands. The deshielding of the N—H proton is relatedto an increase inn electron density in the C—N bond upon complexation,which indicates that the ligands are coordinated to the platinum centrethrough the sulfur atom and not via nitrogen. See J. Zisowsky et al.,incorporated herein by reference in its entirety.

In ¹³C NMR, the C═S resonance of thiones shifted upfield by 5,5-11.1 ppmupon complexation compared to its position in free ligands. This shiftis associated with a decrease in the bond order of C═S bond uponcoordination and a shift of N→C electron density, producing a partialdouble bond character in the C—N bond. See. S. Ahmad et al.; and A. A.Isab et al., each incorporated herein by reference in their entirety.The shift difference in the thiocarbonyl resonance may be related to thestrength of metal-sulfur bond. See Z. Popovic, G. Pavlovic, D.Matkovic-Calogovic, Z. Soldin, M. Rajic, D. Vikic-Topic, D. Kovacek,Inorg. Chim. Acta 306 (2000) 142, incorporated herein by reference inits entirety. The data shows that the Me₂Imt complex with the mostsignificant shift of 13.57 ppm forms the most stable complex. Asobserved previously, changing the group at the N-1 position has a littleeffect on the C-2 shift. See S. Ahmad et al., incorporated herein byreference in its entirety. However, in going from Imt to MeImt andMe₂Imt complex a little downfield shift is observed. In the complexes ofImt and its derivatives a deshielding effect is observed at C-4/5, whilein Diaz and EtDiaz complexes, a deshielding effect is observed at C-4and C-6, but C-5 bears a shielding effect. The deshielding at C-4/6 isdue to an increase in p character of the C—N bond.

TABLE 1 ¹H chemical shifts (ppm) for the ligands and their cis-Pt(II)complexes in DMSO-d₆. Species N-H H-4 H-5 H-6 N-C1 N-C2 N-C3 Imt 7.90 s,4H, 3.59 s, 4H, 3.59 — — — — 1 9.04 s, 4H, 3.68 s, 4H, 3.68 — — — —MeImt 7.93 t, 2H, 3.63 t, 2H, 3.43 — s, 3H, 2.92 — — 2 8.82 t, 2H, 3.75t, 2H, 3.58 — s, 3H, 2.98 — — Me₂Imt — s, 4H, 3.48 s, 4H, 3.48 — s, 6H,2.91 — — 3 — s, 4H, 3.67 s, 4H, 3.67 — s, 6H, 3.18 — — Et₂Imt — s, 4H,3.48 s, 4H, 3.48 — q, 4H, 3.37 t, 6H, 0.97 — 4 — s, 4H, 3.48 s, 4H, 3.48— q, 4H, 3.37 t, 6H, 0.97 — PrImt 7.99 t, 2H, 3.58 t, 2H, 3.41 — t, 2H,3.31 m, 2H, 1.45 t, 3H, 0.73 5 8.63 t, 2H, 3.73 t, 2H, 3.59 — t, 2H,3.36 m, 2H, 1.52 t, 3H, 0.76 iPrImt 7.96 t, 2H, 3.53 t, 2H, 3.38 — m,1H, 4.35 d, 6H, 1.00 — 6 8.77 t, 2H, 3.68 t, 2H, 3.57 — m, 1H, 4.30 d,6H, 1.06 — iPr₂Imt — s, 4H, 3.22 s, 4H, 3.22 — m, 1H, 4.48 d, 6H, 0.99 —7 — s, 4H, 3.41 s, 4H, 3.41 — m, 1H, 4.46 d, 6H, 0.99 — Diaz 7.77 t, 4H,3.15 m, 2H, 1.75 t, 4H, 3.15 — — — 8 8.83 4H, 3.2 m, 2H, 1.74 4H, 3.2 —— — EtDiaz 7.70 t, 2H, 3.62 m, 2H, 1.83 t, 2H, 3.28 q, 2H, 3.12 t, 3H,1.02 — 9 8.44 t, 2H, 3.56 m, 2H, 1.85 t, 2H, 3.34 q, 2H, 3.27 t, 3H,1.05 — Diap 7.70 t, 4H, 3.18 t, 4H, 1.67 t, 411, 1.67 — — — 10 8.74 t,4H, 3.20 t, 4H, 1.62 t, 411, 1.62 — — — s: singlet, d: doublet, t:triplet, q: quartet; m: multiplet

TABLE 2 ¹H and ¹³C chemical shifts (ppm) for the ligands and theircis-Pt(II) complexes in D₂O Species C-2 C-4 C-5 C-6 N-C1 N-C2 N-C3 Imt182.11 45.38 45.38 — — — —  1 174.89 45.96 45.96 — — — — MeImt 181.3842.00 51.82 — 34.35 — —  2 173.92 42.88 52.50 — 34.07 — — Me₂Imt 180.4648.73 48.73 — 34.80 — —  3 166.89 50.29 50.29 — 36.07 — — Et₂Imt 178.7446.13 46.13 — 42.69 11.92 —  4 170.95 47.32 47.32 — 43.73 12.10 — PrImt180.87 49.14 48.86 42.11 20.65 11.09  5 169.74 50.02 48.92 — 42.97 20.6410.95 iPrImt 179.70 42.21 43.73 — 48.18 19.55 —  6 172.60 42.94 44.69 —48.90 19.23 — iPr₂Imt 171.05 48.25 48.25 — 41.52 19.10 —  7 165.55 48.8648.86 — 41.22 18.94 — Diaz 173.34 41.00 19.25 41.00 — — —  8 166.7841.03 18.86 41.03 — — — EtDiaz 173.36 41.14 20.93 46.14 49.54 12.33 —  9165.54 41.38 20.31 47.53 49.61 12.51 — Diap 183.99 45.86 26.99 26.99 — —— 10 177.29 47.20 26.80 26.80 — — —

Example 3 In vitro Cytotoxic Activity Against, A549, MCF7 and HTCJ5Human Cancer Cell Lines

The cis-[Pt(NH₃)₂(thione)₂].2NO₃ complexes were evaluated for their invitro cytotoxic activity against A549 (human lung cancer), MCF-7 (humanbreast cancer) and HTC15 (human colon cancer) cell lines. The cells wereseeded at 4×10³ cells/well in 100 μL DMEM containing 10% FBS in 96-wellstissue culture plate and incubated for 72 h at 37° C., 5% CO₂ in the airand 90% relative humidity in the CO₂ incubator. After incubation, 100 μLof each sample solution (50, 25, 12.5 and 6.25 μM), prepared in DMEM,were added to cells and the cultures were incubated for 24 h. The mediumof wells was discarded and 100 μL DMEM containing MTT(3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium Bromide) (5 mg/mL)was added to the wells and incubated in a CO₂ incubator at 37° C. indark for 4 h. After incubation, purple colored formazan (artificialchromogenic dye, a product of the reduction of water insolubletetrazolium salts e.g., MMT by dehydrogenases and reductases) in thecells is produced and appeared as dark crystals in the bottom of thewells. The resultant crystals were solubilized by adding 100 of DMSO ineach well. The solution was thoroughly mixed to dissolve the formazancrystals, producing a purple solution. The absorbance of the 96-wellsplate was taken at 570 nm with Labsystems Multiskan EX-Enzyme-linkedimmunosorbent assay (EX-ELISA) reader against a reagent blank. The IC₅₀values were calculated from three independent experiments by generatingan equation of logarithmic trendline of percentage cell viabilityagainst concentration compounds in Microsoft excel.

Antitumor Activity. In vitro cytotoxic properties of ten newcis-[Pt(NH₃)₂(Thione)₂].2NO₃ complexes were evaluated against threehuman cancer cell lines, which are: A549 (human lung carcinoma), MCF7(human breast carcinoma), and HCTIS (human colon adenocarcinoma) celllines and compared with cytotoxicity of cisplatin and carboplatin underthe same conditions. The cytotoxicity of cisplatin, carboplatin and thecomplexes was obtained by the stipulated increase in theirconcentrations against fixed number of human cancer cells. The IC₅₀values were obtained from curves between the complexes concentration andviability percentage of the cells, and are listed, in Table 3.

The IC₅₀ values of the complexes against A549 cell lines are in therange of 50 to 108 μM. Cisplatin was found to be the most effective forthese cells. Four of the ten studied complexes, 1, 6, 7 and 10 (havingthe IC₅₀ values 53, 55, 50 and 52 μM respectively) exhibited in vitrocytotoxicity that is comparable to cisplatin but about 1-4 fold betterthan that of carboplatin. Moreover, the inhibition effect of complex 5,8 and 9 is nearly same as that of carboplatin. For MCF7 cells, cisplatinis highly potent, while carboplatin, as well as the investigatedcomplexes, displayed poor antiproliferative potency as indicated by highIC₅₀ values. However, one of the compounds, 3 was tound to have agreater cytotoxic effect than carboplatin against this cell with IC₅₀ of58 μM. Against HCT15 cell lines, all the complexes were noticed to havelower cytotoxicity than cisplatin. But, with respect to carboplatin fourcomplexes, 5, 6, 7, 10 displayed lower IC₅₀ values, while complex 3 hasnearly same value as carboplatin.

The survival of the cells (A549, MCF7 and FICT15) as a function of theconcentration of compounds 1-10 is illustrated in FIGS. 4A-4B; 5A-5B,and 6A-6B which respectively show rffect of concentration of complexes1-10 on viability of A549 cells (FIG. 4A-4B) effect of concentration ofcomplexes 1-10 on viability of MCF7 cells (FIG. 5A-5B), and Effect ofconcentration of complexes 1-10 on viability of HCT15 cells (FIG.6A-6B).

TABLE 3 IC₅₀ Values in (μM) of prepared compounds, against four humantumor cell lines Compounds A549 MCF7 HCT15 Cisplatin  42 ± 2  23 ± 3 32± 2 Carboplatin  70 ± 2  63 ± 2 53 ± 2  1  53 ± 2 101 ± 2 82 ± 1  2  85± 1  82 ± 1 75 ± 2  3  68 ± 1  58 ± 1 54 ± 1  4 108 ± 2  97 ± 3 97 ± 3 5  72 ± 2  74 ± 2 51 ± 2  6  55 ± 1  81 ± 3 48 ± 1  7  50 ± 2  78 ± 252 ± 1  8  75 ± 2  90 ± 2 76 ± 1  9  73 ± 1 103 ± 3 90 ± 2 10  52 ± 2 71 ± 1 41 ± 1 ^(a)Errors are standard deviations determined from atleast three independent experiments.

The experimental results are presented as the micro-mole concentrationof 50% cell growth inhibition (IC₅₀) of each drug. The MTT assay wasperformed in three independent experiments, each in triplicate. Thecancer cell lines used are A549 (human lung cancer), MCF-7 (human breastcancer) and HTC15 (human colon cancer) cell lines.

As shown herein, a new series of cis-diamine platinum(II) complexes(1-10) with the general formula, cis-[Pt(NH₃)₂(Thione)₂].2NO₃ have beensynthesized and characterized using both elemental analysis andspectroscopic methods. The spectroscopic data strongly supported thatthe thione ligands are coordinated to the Pt(II) centre through thesulfur atom. in vitro cytotoxicity of some complexes demonstrated acomparable cytotoxicity to cisplatin and better than carboplatin.

Terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention.

The headings (such as “Background” and “Summary”) and sub-headings usedherein are intended only for general organization of topics within thepresent invention, and are not intended to limit the disclosure of thepresent invention or any aspect thereof. In particular, subject matterdisclosed in the “Background” may include novel technology and may notconstitute a recitation of prior art. Subject matter disclosed in the“Summary” is not an exhaustive or complete disclosure of the entirescope of the technology or any embodiments thereof. Classification ordiscussion of a material within a section of this specification ashaving a particular utility is made for convenience, and no inferenceshould be drawn that the material must necessarily or solely function inaccordance with its classification herein when it is used in any givencomposition.

As used herein, the words “a” and “an” and the like carry the meaning of“one or more” unless the context clearly indicates otherwise.

Within the description of this disclosure, where a numerical limit orrange is stated, the endpoints are included unless stated otherwise.Also, all values and subranges within a numerical limit or range arespecifically included as if explicitly written out. For example, a rangeof 0 to 10 wt % includes 0. 0.25, 0.5, 1, 1.5, 2, 2.5, 3, 4, 5, 6, 7, 8,9, 9.75, 9.99, <10, and 10.

The terms “including”, “such as”, “for example” and the like notintended to limit the scope of the present disclosure. They generallyrefer to one or more elements falling with a class or genus of othersimilar elements.

It will be further understood that the terms “comprises” and/or“comprising,” when used in this specification, specify the presence ofstated features, steps, operations, elements, and/or components, but donot preclude the presence or addition of one or more other features,steps, operations, elements, components, and/or groups thereof.

As used herein, the term “and/or” includes any and all combinations ofone or more of the associated listed items and may be abbreviated as“/”.

Links are disabled by insertion of a space or underlined space into alink, for example, before “www” or after “//” and may be reactivated byremoval of the space.

As used herein in the specification and claims, including as used in theexamples and unless otherwise expressly specified, all numbers may beread as if prefaced by the word “substantially”, “about” or“approximately,” even if the term does not expressly appear. The phrase“about” or “approximately” may be used when describing magnitude and/orposition to indicate that the value and/or position described is withina reasonable expected range of values and/or positions. For example, anumeric value may have a value that is +/−0.1% of the stated value (orrange of values), +/−1% of the stated value (or range of values), +/−2%of the stated value (or range of values), +/−5% of the stated value (orrange of values), +/−10% of the stated value (or range of values),+/−15% of the stated value (or range of values), +/−20% of the statedvalue (or range of values), etc. Any numerical range recited herein isintended to include all sub-ranges subsumed therein.

Disclosure of values and ranges of values for specific parameters (suchas temperatures, molecular weights, weight percentages, etc.) are notexclusive of other values and ranges of values useful herein. It isenvisioned that two or more specific exemplified values for a givenparameter may define endpoints for a range of values that may be claimedfor the parameter. For example, if Parameter X is exemplified herein tohave value A and also exemplified to have value Z, it is envisioned thatparameter X may have a range of values from about A to about Z.Similarly, it is envisioned that disclosure of two or more ranges ofvalues for a parameter (whether such ranges are nested, overlapping ordistinct) subsume all possible combination of ranges for the value thatmight be claimed using endpoints of the disclosed ranges. For example,if parameter X is exemplified herein to have values in the range of 1-10it is also envisioned that Parameter X may have other ranges of valuesincluding 1-9, 2-9, 3-8, 1-8, 1-3, 1-2. 2-10, 2.5-7.8, 2-8, 2-3, 3-10,and 3-9, as mere examples.

As used herein, the words “preferred” and “preferably” refer toembodiments of the technology that afford certain benefits, undercertain circumstances. However, other embodiments may also be preferred,under the same or other circumstances. Furthermore, the recitation ofone or more preferred embodiments does not imply that other embodimentsare not useful, and is not intended to exclude other embodiments fromthe scope of the technology. As referred to herein, all compositionalpercentages are by weight of the total composition, unless otherwisespecified. As used herein, the word “include,” and its variants, isintended to he non-limiting, such that recitation of items in a list isnot to the exclusion of other like tems that may also be useful in thematerials, compositions, devices, and methods of this technology.Similarly, the terms “can” and “may” and their variants are intended tobe non-limiting, such that recitation that an embodiment can or maycomprise certain elements or features does not exclude other embodimentsof the present invention that do not contain those elements or features.

Although the terms “first” and “second” may he used herein to describevarious features/elements (including steps), these features/elementsshould not be limited by these terms, unless the context indicatesotherwise. These terms may be used to distinguish one feature/elementfrom another feature/element. Thus, a first feature/element discussedbelow could be termed a second feature/element, and similarly, a secondfeature/element discussed below could be termed a first feature/elementwithout departing from the teachings of the present invention.

The description and specific examples, while indicating embodiments ofthe technology, are intended for purposes of illustration only and arenot intended to limit the scope of the technology. Moreover, recitationof multiple embodiments having stated features is not intended toexclude other embodiments having additional features, or otherembodiments incorporating different combinations of the stated features.Specific examples are provided for illustrative purposes of how to makeand use the compositions and methods of this technology and, unlessexplicitly stated otherwise, are not intended to be a representationthat given embodiments of this technology have, or have not, been madeor tested.

All publications and patent applications mentioned in this specificationare herein incorporated by reference in their entirety to the sameextent as if each individual publication or patent application wasspecifically and individually indicated to he incorporated by reference,especially referenced is disclosure appearing in the same sentence,paragraph, page or section of the specification in which theincorporation by reference appears.

The citation of references herein does not constitute an admission thatthose references are prior art or have any relevance to thepatentability of the technology disclosed herein. Any discussion of thecontent of references cited is intended merely to provide a generalsummary of assertions made by the authors of the references, and doesnot constitute an admission as to the accuracy of the content of suchreferences.

1. A method for treating a proliferative disease, disorder, orcondition, comprising: administering to a subject in need thereof acomplex of formula [Pt(N R₁R₂)₂(thione)₂].2[anion]; wherein R₁ and R₂are, independently, hydrogen, alkyl or aryl.
 2. The method of claim 1,wherein the thione used to produce the complex is selected from thegroup consisting of:

wherein each R is independently a H, alkyl, or aryl.
 3. The method ofclaim 1, wherein the thione used to produce the complex is selected fromthe group consisting of:

wherein in (a) R═R′═H; (b) R═H, R′═CH₃; (c) R═CH₃, R^(/)═CH₃; (d)R═R′═C₂H₅; (e) R═H, R′═C₃H₇; (f) R═H, R′=i-C₃H₇; (g) R═R′=i-C₃H₇; (h)R═H; (i) R═C₂H₅; and (j) is 1,3-Diazepane-2-thione (Diap).
 4. The methodof claim 1, wherein the complex has the formula Pt(NH₃)₂(thione)₂].2NO₃or a variant complex wherein one or two of the NO₃ anions are replacedwith one or more different anions.
 5. The method of claim 1, wherein thecomplex is selected from the group consisting of at least one ofcis-[Pt(NH₃)₂(Imt)₂].2NO₃ (1), cis-[Pt(NH₃)₂(MeImt)₂].2NO₃ (2),cis-[Pt(NH₃)₂(Me₂Imt)₂].2NO₃ (3), cis-[Pt(NH₃)₂(Et₂Imt)₂].2NO₃ (4),cis-[Pt(NH₃)₂(PrImt)₂].2NO₃ (5), cis-[Pt(NH₃)₂(iPrImt)₂].2NO₃ (6),cis-[Pt(NH₃)₂(iPr₂Imt)₂].2NO₃ (7), cis-[Pt(NH₃)₂(Diaz)₂].2NO₃ (8),cis-[Pt(NH₃)₂(EtDiaz)₂].2NO₃ (9), and cis-[Pt(NH₃)₂(Diap)₂].2NO₃ (10),or a variant complex wherein one or two of the NO₃ anions are replacedwith one or more different anions; wherein Imt isimidazolidine-2-thione, MeImt is N-methylimidazolidine-2-thione, Me₂Imtis N,N′-dimethylimidazolidine-2-thione, Et₂Imt isN,N′-diethylimidazolidine-2-thione, PrImt isN-propylimidazolidine-2-thione, iPrImt isN-(isopropyl)imidazolidine-2-thione, iPr₂Imt isN,N′-(di-isopropyl)imidazolidine-2-thione, Diaz is diazinane-2-thione,and Diap is 1,3-Diazepane-2-thione.
 6. The method of claim 1, whereinthe complex is selected from the group consisting of at least one ofcis-[Pt(NH₃)₂(Imt)₂].2NO₃ (1), cis-[Pt(NH₃)₂(MeImt)₂].2NO₃ (2),cis-[Pt(NH₃)₂(Me₂Imt)₂].2NO₃ (3), cis-[Pt(NH₃)₂(Et₂Imt)₂].2NO₃ (4),cis-[Pt(NH₃)₂(PrImt)₂].2NO₃ (5), cis-[Pt(NH₃)₂(iPrImt)₂].2NO₃ (6),cis-[Pt(NH₃)₂(iPr₂Imt)₂].2NO₃ (7), cis-[Pt(NH₃)₂(Diaz)₂].2NO₃ (8),cis-[Pt(NH₃)₂(EtDiaz)₂].2NO₃ (9), and cis-[Pt(NH₃)₂(Diap)₂].2NO₃ (10)wherein Imt is imidazolidine-2-thione, MeImt isN-methylimidazolidine-2-thione, Me₂Imt isN,N′-dimethylimidazolidine-2-thione, Et₂Imt isN,N′-diethylimidazolidine-2-thione, PrImt isN-propylimidazolidine-2-thione, iPrImt isN-(isopropyl)imidazolidine-2-thione, iPr₂Imt isN,N′-(di-isopropyl)imidazolidine-2-thione, Diaz is diazinane-2-thione,and Diap is 1,3-Diazepane-2-thione.
 7. The method of claim 1, whereinthe proliferative disease, disorder or condition is cancer.
 8. Themethod of claim 1, wherein the proliferative disease, disorder orcondition is not cancer.
 9. The method of claim 1, wherein theproliferative disease, disorder or condition is cancer that is or hasbecome resistant to cisplatin or wherein the complex produces lessnephrotoxicity or neurotoxicity than the same dose of cisplatin.
 10. Themethod of claim 1, wherein the proliferative disease, disorder, orcondition is breast cancer.
 11. The method of claim 1, wherein theproliferative disease, disorder, or condition is colon cancer.
 12. Themethod of claim 1, wherein the proliferative disease, disorder, orcondition is lung cancer.
 13. A cis-diamine platinum(II) thione complexof the formula [Pt(N R₁R₂)₂(thione)₂].2[anion]; wherein R₁ and R₂ are,independently, hydrogen, alkyl or aryl.
 14. The cis-diamine platinum(II)thione complex of claim 12, wherein the thione molecule used to producethe complex is selected from the group consisting of:

wherein R, independently, is H, alkyl, or aryl.
 15. The cis-diamineplatinum(II) thione complex of claim 14, wherein the thione moleculeused to produce the complex is selected from the group consisting of:

wherein in (a) R═R′═H; (b) R═H, R′═CH₃; (c) R═CH₃, R^(/)═CH₃; (d)R═R′═C₂H₅; (e) R═H, R′═C₃H₇; (f) R═H, R′=i-C₃H₇; (g) R═R′=i-C₃H₇; (h)R═H; (i) R═C₂H₅; and (j) is 1,3-Diazepane-2-thione (Diap).
 16. Thecis-diamine platinum(II) thione complex of claim 14, wherein theplatinum (II) complex has the formula Pt(NH₃)₂(Thione)₂].2NO₃ or avariant complex wherein one or two of the NO₃ anions are replaced withone or more different anions.
 17. The cis-diamine platinum(II) thionecomplex of claim 14, wherein the complex is selected from the groupconsisting of at least one of cis-[Pt(NH₃)₂(Imt)₂].2NO₃ (1),cis-[Pt(NH₃)₂(MeImt)₂].2NO₃ (2), cis-[Pt(NH₃)₂(Me₂Imt)₂].2NO₃ (3),cis-[Pt(NH₃)₂(Et₂Imt)₂].2NO₃ (4), cis-[Pt(NH₃)₂(PrImt)₂].2NO₃ (5),cis-[Pt(NH₃)₂(iPrImt)₂].2NO₃ (6), cis-[Pt(NH₃)₂(iPr₂Imt)₂].2NO₃ (7),cis-[Pt(NH₃)₂(Diaz)₂].2NO₃ (8), cis-[Pt(NH₃)₂(EtDiaz)₂].2NO₃ (9), andcis-[Pt(NH₃)₂(Diap)₂].2NO₃ (10), or a variant complex wherein one or twoof the NO₃ anions are replaced with one or more different anions;wherein Imt is imidazolidine-2-thione, MeImt isN-methylimidazolidine-2-thione, Me₂Imt isN,N′-dimethylimidazolidine-2-thione, Et₂Imt isN,N′-diethylimidazolidine-2-thione, PrImt isN-propylimidazolidine-2-thione, iPrImt isN-(isopropyl)imidazolidine-2-thione, iPr₂Imt isN,N′-(di-isopropyl)imidazolidine-2-thione, Diaz is diazinane-2-thione,and Diap is 1,3-Diazepane-2-thione.
 18. The cis-diamine platinum(II)thione complex of claim 14 , wherein both anions are NO₃.
 19. Apharmaceutical composition comprising at least one cis-diamineplatinum(II) thione complex of claim 13 in combination with at least onepharmaceutically acceptable carrier or excipient.
 20. The pharmaceuticalcomposition of claim 19 that further comprises another anticancer drug,chemotherapeutic agent, or immunopotentiator.